This invention pertains to orthotics, and more particularly to apparatus that assists a person to walk.
In normal walking, at the end of each step a rearward foot is in contact with the ground at a distance behind a forward foot. To take another step, the rearward foot must be lifted and swung forwardly through combined actions of the hip, knee, and leg. Simultaneously, the rearward foot must pivot upwardly about the ankle such that the toes lift off the ground.
Some persons, such as those with multiple sclerosis, suffer from a condition commonly known as foot drop. A person with foot drop lacks sufficient muscular control to pivot his foot upwardly about the ankle. In that situation, at the end of a walking step in which the affected foot is behind the forward foot, the person may be able to lift and swing his leg to bring the affected foot forward. However, he is not able to simultaneously pivot his foot upwardly about the ankle. Consequently, if the person makes a normal forward stepping movement with his leg, the toes of the affected foot drag along the ground. A greatly exaggerated lifting of the leg is required to avoid dragging the toes, to the extent that anything remotely resembling normal walking is impossible. In severe cases, the person may have difficulty even bending his knee or swinging his leg from the hip. As a result, such persons are often confined to a wheelchair, or they walk by shuffling their feet using an awkward combination of leg, hip, and knee motions.
Various equipment has been developed to aid persons with foot drop. Examples of such prior devices may be seen in U.S. Pat. Nos. 4,329,982 and 4,566,447. The devices of the two foregoing patents have the disadvantage of requiring modifications to the shoe of the user. In addition, neither aforementioned device is able to assist a person to bend his knee or lift his leg from the hip. A further disadvantage of the device of the U.S. Pat. No. 4,566,447 patent is that the angle of the connection between a leg band and the foot is such that it is difficult to wear with conventional slacks or trousers.
U.S. Pat. Nos. 4,817,589 and 5,257,969 show foot supports that utilize the ankle as an anchor for a strap that goes to the front of the foot or shoe. The constant force on the ankle makes the assists of the U.S. Pat. Nos. 4,817,589 and 5,257,969 patents uncomfortable to wear for long. In addition, the assists of the two foregoing patents do not help a person bend his knee or lift his leg.
U.S. Pat. No. 5,112,296 shows an electronic based orthosis that is quite complicated and expensive. The location of a foot strap between the heel and the ball of the foot provides only minimal leverage for pivoting the foot about the ankle.
Thus, a need exists for an improved way to assist persons suffering from foot drop.
In accordance with the present invention, a foot lift assist is provided that both enables and encourages a person with foot drop to walk in a nearly normal manner. This is accomplished by an apparatus that includes a long elastic cord extending from a person""s hip and acting on his foot forwardly of the ball of the foot.
The foot lift assist is anchored at the person""s hip by a belt around his waist. The elastic cord is hooked at one end to the belt over the hip associated with the foot with foot drop. The elastic cord second end is connected by a snap or shackle to a foot strap. The connection point of the elastic cord to the foot strap is to the outside of the longitudinal centerline of the foot.
According to one aspect of the invention, the foot strap is a fully flexible foot strap. The fully flexible foot strap comprises a flexible strap that is adjustable to suit a person""s foot or shoe. The flexible strap wraps around the shoe or foot at a location forward of the ball of the foot. To enhance the comfort and performance of the foot lift assist, there is a pad on the inside of the flexible strap that overlies the little toe. The pad is designed to contact the top of the sole of a shoe. In that manner, the flexible strap does not slip circumferentially around the shoe. To further distribute stress in the region of the little toe, a semi-rigid strip can be added between the flexible strap and the pad. Preferably, the outside of the flexible strap under the foot is coated with a non-slip and abrasion resistant material.
When the foot lift assist is in place on a person""s affected foot, shifting at least some of his weight to the other foot enables the elastic cord to bend the leg and lift the foot from the ground. The location of the lifting force near the person""s toes naturally compensates for foot drop by pivoting the foot upwardly about the ankle. With a little practice, the person is able to walk in a manner that approaches a normal gait. The location of the connection between the elastic cord and the fully flexible foot strap on the outside of the person""s foot keeps the elastic cord off the person""s knee while he is walking and thus contributes to the performance and comfort of the foot lift assist. The pad provides protection to the little toe during the repeated lifting forces exerted on the flexible strap. The coating on the underside of the flexible strap reduces the possibility of slipping, and it also reduces wear on the flexible strap. The long length of the elastic cord between the belt and the flexible strap enables conventional pants or slacks to be worn without hindering performance of the foot lift assist and without calling attention to the presence of the elastic cord. The snap enables the flexible strap to be quickly disconnected from the elastic cord when the person sits between walking activities.
In a modified embodiment of the invention, the foot strap includes a metal plate that underlies the foot or shoe. The metal plate is useful when a person walks on abrasive surfaces. The metal plate is bonded to a strap. Like the fully flexible foot strap, the connection between the elastic cord and the foot strap with the metal plate is to the outside of the longitudinal centerline of the person""s foot.
To assure retention of the metal plate embodiment of the foot strap on the foot, a heel band can be attached to the metal plate at the inside and outside of the foot. The heel band loops around the heel of the foot or shoe. The snap connection between the foot strap and the elastic cord provides easy interchangeability between the fully flexible and metal plate embodiments of the foot strap of the invention.
The method and apparatus of the invention, using a long elastic cord between a person""s hip and his foot, thus provides a lifting force to the front of the foot that also lifts the leg. The probability of dragging the toes while walking is remote, even though the person has minimal if any ability to pivot his foot upwardly at the ankle.
Other advantages, benefits, and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention.